This project investigates two fundamental problems in biology: (1) the role of dynamic patterns in embryology and evolution, and (2) kinetics of enzymes located in cell membranes. The first area involves a demonstration of the role which simultaneous reaction and diffusion might play in the formation of biological patterns such as organ shapes and surface markings. The second area involves investigation of the effect of diffusion limitation by cell membranes on the kinetics of enzymes contained in them. Digital computer simulation and numerical solution of partial differential equations are the main tools in these investigations.